flag pole widow’s walk
I need to replace a flag pole mounted atop a 10/12 roof on a historic coastal house in MA. The existing locust flag pole is ~20′ tall, ~6″ diameter at the base and extends through the roof where it is anchored to the collar ties and rafters. Water leakage has been a problem despite extensive recent flashing efforts. Water appears to be working its way down deep cracks in the wood and bypassing the flashing. I’m reluctant to cut kerfs into the pole for fear of weakening the pole in the face of gale force winds.
The second issue is that this flagpole was the sole anchor point for a widow’s walk deck. The deck ~6’x6′ straddles the ridge with the flag pole coming straight up through the center. When the house was reroofed 2 yrs ago, the deck was removed. The owners’ are reluctant to rebuild the deck until the flagpole issue is resolved. Assuming the flagpole is replaced and/or the leaking is resolved, I’d like some ideas on attaching the deck independant of the flagpole.
Re the flag pole, I wonder if there might not be a way to pressure-inject epoxy or some such into the cracks to seal them.
Another option to consider is to simply deal with the leakage with some sort of drip pan and possibly a condensate pump to remove the water.
I figure your pole is about 4 cubic feet at 46 pounds per cubic foot, or 184 pounds, or maybe down to 140 or so, depending on the taper. (But somebody please check my numbers.) Something that two hefty guys could handle on level ground, but not on a 10/12 roof, and not if standing on wood shingles. Probably a crane is the ticket -- expensive but safe.
Anchoring the widows's walk, I suspect, depends a lot on the details of the framing and roof. Wood shingles? How are others in the area anchored? (There must be some other good examples.)
When attaching something structural to a roof I'm a big fan of using some version of stainless steel C channel 8 - 10" long running up the ridge - it's easy to work with, strong, easy to seal, works in all climates. In your case I'd probalby go with two pieces of angle in a C-channel configuration held together with a couple of stainless 5/16" bolts and nylock nut - this allows the lower half (one piece of angle) to sit flat with the roof and the upper half to be positioned level so it's easier to build off of. If cosmetics are a prime consideration having the brackets welded is cleaner - perhaps even some shape added so they aren't as angular. As for size, 1/8" thick C channel or angle is commonly available, easy to work with and quite stiff for this purpose, but I'd not hesitate to use 3/16" since I enjoy the extra thickness - it just looks solid.
To finish the brackets that are visible I simply use a random orbit sander to give a uniform dull look, but a coarse sand blasted finish would be even better.
Timberlock screws into the rafters gives you an easy but secure and load rated connection (the screws are load rated anyway - building departments don't seem to question the steel brackets since it's really overkill for what you're building). There is one form of timberlock with a flat head and an 8 sided star type bit like a Torx with a few extra points that is flat enough that roofing can cover it easily and it just looks cleaner on exposed fasteners.
On the roof deck I'll put down a 3' square layer of ice and water under where each bracket meets the roof (with the lower edge of the ice and water shedding water out over the lower shingles, and caulk the bracket down to this (and caulk the timberlocks holding the bracket to the roof) and add roofing up and over the area. The shape of the C channel is really easy to work into most shingle types.
On the roof attachments like this that I've had to have pass a structural inspection the inspectors just want to know the brackets are over something solid that will support the point load. On old framing that might otherwise already be overspanned, this was addressed by simply adding a 4x4 post down through the attic to a load bearing wall. The rafter and decking keep the bracket in position, but the load is really carried by the post. Even on something as light weight as your little deck, that issue may come up since I'm sure there is some form of code required load per sqft of deck.
To seal up the flag pole I'd probably inject as much gorilla glue into the cracks as I thought would stay in place for a few minutes and brush the checked surface liberally with the stuff and wrap 6" wide shrinkwrap over the area until it sets. Ideally this would be at and just above where the flashing meets for 6" or so if that's not visually a problem (I'm thinking the deck covers this area?).
As it expands some of the glue will seal, and the larger areas may or may not completely seal, but a second application would seem to take care of some quite large checks. The shrinkwrap should be put on tight since it's going to assit in forcing the expanding glue into areas the brush and injector couldn't. I go to vet supply places and buy the largest size needles, which are about 1/16" in diameter and that works ok with glue. The larger the syringe the easier it is to get glue into, but the harder you have to push to get the glue out (don't try to suck up glue, simply pull the plunger out, fill, and replace the plunger).
It sounds like a fun project!